Measure and record the distance traveled by the air bubble in potometer in 10 minutes using a ruler// Calculate the rate of transpiration using the formula : Distance traveled by air bubble÷time (cm/min)

Procedure

1.Setup the apparatus as shown in diagram above.

2.Choose a leafy shoot and cut the shoot end in water.

3.Insert cut stem in the potometer.

4.Adjust and mark the initial position of the air bubble.

5.Dry the surface of the leaves before the start of the experiment.

6.The light intensity / temperature of the surrounding must be maintainedthroughout the experiment.

7.Measure the distance traveled by the air bubble in 10 minutes for eachcondition of air movement

8.Carry out the experiment in still air, slow and fast moving fan.

9.Use the same type and length of leafy shoot for all 3 experiments.

Precaution

1.The joint end of the stem and apparatus is smeared with vaseline toensure no water leakage and the apparatus is airtight.

2.The surface of the leaves must be dry before the start of the experiment.

Recording data/ result

Condition of air/Speed of fan

Distance traveled by air bubble in 10 min

(cm)

Rate of transpiration :

Distance traveled by air bubble/Time

(cm/min)

Still air (Fan speed 0)

Slow moving air (Fan speed 1)

Fast moving air (Fan speed 3)

Conclusion

Hypothesis is accepted. The faster the air movement, the greater/higher the rate of transpiration of a plant.